waiting-time displays for bus passengers team a: huanwen qu, laurence cabenda, kang ning
TRANSCRIPT
Waiting-time Displays for Bus Passengers
Team A: Huanwen Qu ,
Laurence Cabenda ,Kang Ning
Assignment
●The buses equip with GPS and mobile phones. Call into a central system to report their present location.●The bus stands will get LED displays controlled by a microprocessor which can also communicate by phone. ●The solution of communicating by phone was chosen●The central system knows the geography of the routes of all buses, the typical travel speed.
Requirements
● A high-level specification of the sytem● Give a briefing to the issue and aspects that may
be of importance for this.
Bus stand
Bus stand
Bus stand
Bus stand
Bus
Bus
Central System
Illustration
Central System
Mobilphone network
Auto phone
call
INTERFACE
System
control
Bus speed
calc
Route m
ap calc
Position calc
INTERFACE
Data process
Bus Speed
Bus Stand
Route Map
BUS with GPSBUS stand with LED
UML
Components
Central SystemBus
Bus Stand
Modules of Bus
GPS Receiver Bus Position Sender
Bus Position Report
GPS Receiver
● Contains GPS control system.● Receives bus position from GPS system● Exposes an interface which provides current bus
position to the Bus Position Report module.– GetPosition : POSITION
Bus Position Sender
● Contains mobile phone communication system.● Provides Wireless Data Link to the bus.● Exposes an interface to Bus Position Report
module.– SendPosition : POSITION
Receives position data and sends data to the Central System.
Bus Position Report
● Reports current bus position to Central System periodically.
● There is a timer in the module. When the timer is triggered, the module requests the current bus position from GPS Receiver module and sends this position to Central System through Position Sender module.
Timer --> SendPosition (GetPosition)
Modules of Bus Stand
Bus Distance Receiver
Bus Distance Display
LED Display
Bus Distance Receiver
● Contains mobile phone communication system.● Provides Wireless Data Link to the bus stand.● Receives bus distance from Central System.● Calls Bus Distance Display module to show
distance data when new data are received.– ShowDistance : DISTANCE
Bus Distance Display
● Shows bus distance data thought LED Display module.– LEDShow (LED)
● Converts bus distance data to LED display data.– DISTANCE -> LED
● Exposes an interface to Bus Distance Receiver module.– ShowDistance : DISTANCE
Converts DISTANCE to LED and shows it.
LED Display
● Shows the distance of the arriving buses on the LED display.
● Contains a LED display control system in the module.
● Exposes an interface which accepts bus distance data with type LED and shows the distance.– LEDShow : LED
Modules of Central System
Bus Position Trace
Route Map
Bus Distance Broadcast
Bus Distance Forecast
Bus Distance SenderBus Position Receiver
Bus Position Receiver
● Contains Mobile Phone Communication system.● Provides Wireless Data Link to the Central
System.● Receives bus positions for buses.● Calls Bus Position Trace module when new
position data arrives.– UpdatePosition position
Bus Distance Sender
● Contains Mobile Phone Communication system.● Provides Wireless Data Link to the Central
System.● Sends bus distance data to bus stands.● Exposes an interface to Bus Distance Broadcast
module.– SendDistance : DISTANCE
Accepts DISTANCE data and sends it to bus stands.
Bus Position Trace
● Manages position information of all buses dynamically
● Two interfaces:– UpdatePosition : POSITION
Updates a bus position.
– GetPosition : POSITION
Get a bus position from the trace.
Bus Distance Broadcast● Broadcasts bus distance data to all bus stands
periodically.● Manages a bus stands list.
– AllStands : STAND● There is timer in the module. When timer is
triggered, it calculates all bus distance data and sends them to all bus stands.
Timer --> for each stand in AllStands
distance = Forecast stand
SendDistance distance
Bus Distance Forecast
● Forecasts how much time it takes from a bus to a bus stands according to a typical bus speed and the route.
● The module can query bus position from Bus Position Trace module and query route map from Route Map module.
● Interface:– Forecast : STAND -> DISTANCE
Route Map
● Contains all information of bus routes and bus stands.
● Provides some interfaces for Bus Distance Forecast module to query data of bus routes and bus stands.
Discuss Requirements Accuracy
● Time intervals buses send GPS position● Time intervals server update the bus-stands● Accuracy versus time overhead.